In an epitaxial growth method which grows a semiconductor thin film on a semiconductor substrate, raw material gas is supplied into a high-temperature reactor, and a thin film is grown by thermal decomposition and vapor-phase reaction. In a vapor-phase growth apparatus which is an apparatus for executing the epitaxial growth method, since a substrate is mounted on a susceptor, and heating is performed from the lower surface side of the susceptor to heat the substrate to a high temperature, the lower surface side of the susceptor is raised to a high temperature. The term “susceptor” refers to a support on which a plurality of substrates can be mounted on the upper surface thereof, and which is heated and transmits heat to the substrates.
In addition, since raw material gas flows on the upper surface side of the susceptor, the upper surface side of the susceptor is deprived of heat by raw material gas.
For this reason, a difference in temperature occurs between the upper surface side and the lower surface side of the susceptor, thermal stress occurs in the susceptor, and cracking or fracture occurs in the susceptor.
In order to solve this problem, for example, in Patent Document 1, a skirt portion which hangs down on an outer periphery of a susceptor is provided, a minute gap is provided at the outer periphery of the susceptor between a ring arranged near the susceptor and the skirt portion, and the upper space and the lower space of the susceptor communicate with each other by the minute gap.
Accordingly, a temperature deviation above and below the outer periphery of the susceptor is eliminated, and there is no case where cracking or fracture occurs.